Method of producing motion-picture films



y 1945. 1. M. TERWILLIGER 2,375,962

METHOD OF PRODUCING MOTION PICTURE FILMS Original Filed Aug. 12} 1959.fl AA/ J14. jQW/LL/GEB, INVENTOR.

// V TT RNEY.

Patented May l 5,-1 4 v UNITED sTATl-zs PATENT oFFlcE Ivan M.Terwllllger, Pasadena, Calif.

Original application August 12, 1939, Serial No. 289,877, new Patent No.2,322,752, dated June 29, 1943. Divided and this application March 29,1943, Serial No. 480,964

8 Claims.

My invention relates generally to the art of cinematography, and moreparticularly to the production of pictures which, when projected upon ascreen, give the illusion of depth.

This application is a division of my copending application Serial No.289,8'77, filed August 12, 1939, now Patent Number 2,322,752 issued June29, 1943, and entitled "Motion picture film which was a continuation ofmy application Serial. No. 183,696, filed January 6, i938.

I-it is an object of my invention to provide a method of producing afilm carrying a plurality of intermingled images having different depthsof field, said images being arranged in various orders or combinations.

it is also an object of my invention to provide a method of producing afilm in which one series oi images having a certain depth of field pre-*dominate over other series or" images having a different depth of field.

Some of the advantages of this type of film which 1 term steropatterninclude the production of the illusion of depth and plasticity ofrelief, increased rounclness in the images, harmonious blending betweenimages of objects at different depths of the field, and a coherentrusion of the variant aspects of the pictures seen upon projection.

it is also an object of my invention to provide a method and means ofvarying the iris opening, which means can be used with conventionalcameras or with variable focus cameras.

Another object or my invention is to provide a film strip of thecharacter mentioned, in which a given portion of each image is inregistration with the same portion of the other images carried in otherframes along said film strip.

These and other objects and advantages of my invention will becomeapparent from the following description of a preferred form thereof, andfrom the accompanying drawing illustrating that form, in which:

Fig. l is a front elevation of a camera lens mount and iris controlmeans, illustrating one form of apparatus which may be used to producethe film of my invention;

Figs. 2 and 3 illustrate optional forms of cams for the apparatus ofFig. l

Fig. 4 is a partial front elevation of a lens mount and auxiliaryoptical element usable in my invention;

Fig. 5 is a perspectiveof said optical element;

and

Fig. 6 is a fragmentary view of the film produced by my invention.

' by varying the position of the cam 52 on the shaft positions to beassumed by the iris opening in producing the film of my invention areindicated by the full line circle ii and the dotted. circle l, thenumeral indicating the larger opening position and the numeral "lindicating the smaller or contracted iris position.

The iris 2? may be provided with a control arm 3 which, in the formillustrated in Fig. l, is pro= vicled. with a contact point or fingeriii adjacent its lower end for a purpose to be hereinafter shown. Theiris control arm is held by a spring a which continually urges itagainst a cam 52.

The camera is provided with a shaft 6 which is connected by gears (notshown) to the main drive shaft of the camera and is synchronized withthe film-advancing mechanism thereof. "lhe cam is provided with a radialslot 5, by means of which it is mounted on shaft '21 for rotationtherewith, it being noted that the cam 52 is mounted eccentrically onthe shaft t and that by virtue of the slot 5, its lateral position withrespect to the shaft may be varied, suitable means being provided forsecuring the cam to the shaft in the desired position The cam 52 is ofsuch size as to bear against the iris control arm contact point it atall times during its rotation, the spring 9 continually urging the pointit into contact with the cam. Consequently, rotation of the cam 52causes lateral movement of the contact point it and control arm 3 whichresults in a variation of the size of the iris 2. The gear connectionbetween the drive shaft of the camera and the shaft 5 may providevarious ratios of rotation, one suitable ratio being 2 to 1, whereby twoframes of the film are caused to pass the exposure aperture for eachrevolution of the cam 52, so that one frame is exposed with the iris inits enlarged position, as illustrated for example by circle 5, and thesuccessive irame is exposed through a contracted iris, for example asillustrated by circle i. It will be understood, of course, that t or byvarying the diameter of the cam, the deree of the iris opening can bevaried, and likewise it will be understood that different combinationsof gears may be employed for the purpose of providing a different numberof frame variatlons per cycle.

It is essential, however, in all of these variations that the irisopening should alwaysbe large enough so that sufllcient light isadmitted to the camera to provide an adequate exposure of the completeframe area of the him under the partioular photographing conditions. Forexample, it may be desired to vary the iris over three, four, or othernumber of frames so that a more gradual change is effected, which can beeasily accomplished by properly proportioning the gear train. while thelimits of variation of iris size may vary widely'with different fllmsensitivities and other ploying a cam such as 53, I produce twice asmany pictures of one depth of focus as I do pictures of the differentdepth of focus, and consequently those pictures of the first depth offocus predominate in number and effect upon the eye. In other words, Ican produce a film in which the images having greater average diffusionpredominate over their counterpart images having greater averagesharpness of contour or vice versa.

Furthermore, it will be apparent that the lens may be focused on anydesired plane in the field, either foreground, middle ground, orbackground, and that this plane will always be in focus, even though therelative diifusion of the images may be varied. For example, the cameramay be focused on the nearest foreground object which is maintained insharp definition in all frames, and the definition of the background maybe varied between sharpness and diffusion by varying. the iris openingsas previously explained. Conversely, the camera may be focused on thebackground, and the foreground images may be I have illustrated amodified form of cam Fill adapted to be mounted on the shaft 6 in placeof the circular cam 52. It will be noted that cam 53 is circular fortwo-thirds of its perimeter, the other one-third comprising a chordof-the circle. The letter T indicates the midpoint of the circular faceof the cam and the letters T and 'I" indicate, respectively, the ends ofthe chord.

By employing the proper gear train and cor rectly proportioning the cam.53, it can be made to rotate once for every three frames which pass theexposure aperture of the camera. Thus it will be seen that two of thethree frames will be exposed while the iris is at a fixed positionduring the time which the control arm contact point If) is following thecircular portion of the cam '32", T and T". The third frame of the cyclewill be exposed at a different iris opening, either larger or smaller asthe case may be while the contact point iii follows the cam surfacebetween T"-T, it being further noted that during this latter exposure,the iris opening will make a com plete cycle of wide to narrow to wide,or vice versa, depending upon the correlation between the cam and thecontrol arm 3.

In this manner, I produce a film having two successive frames with thesame depth 01' focus followed by a frame having a difierent depth offluctuated between sharpness and difiusion on consecutive frames, or thecamera may be focused on the plane of the middle ground and both theobjects in the foreground and background may be varied in similarmanner. I thus produce a film which on projection will vary the depth offocus within a, scene of pictures, each individually harmonious, whilemaintaining a selected depth plane in relatively sharp focus throughout.

Referring now to Fig. 3, it is seen that I have there illustratedanother type of cam indicated by the numeral M which is adapted to givea.

as non-progressive variation or series of variations among frames. Thecam 54 is likewise adapted to be rotated with the shaft 4 with a. propergear train which, for example, may be proportioned so as to cause onecomplete rotation of the cam 54 so for each foul frames of film whichare exposed of focus, the images of the different series beingintermingled, it being understood, of course, that the number of imagesof either series may predominate over the other.

As is well known to those familiar with the art of photography, anexposure made through a small aperture will have a greater depth offocus than an exposure made through a larger aperture. By thus varyingthe depth of focus between frames, I provide on the frame exposedthrough the small aperture an image having more sharpness of contour andin which a greater number of objects in different planes of the fieldhave a relatively distinct contour, while on those frames photographedthrough the larger aperture, I produce images in which fewer of theobjects are clearly defined, and those objects located in planes of thefield, distant from the plane of focus of the camera are relativelydiffused. By emat the aperture. The faces A and B may be the some andthe faces C and B may he the same, but in this case the cam should beeccentrically mounted on shaft, l as indicated. The same result may beaccomplished by having all of the cam faces diiferent. In either eventthe order of the aperture sizes produced must be nonprogreasive. Forexample, assuming that the cam faces A, B, C, D will produceprogressively larger aperture openings, the order of rotation should beA, D, B, C or other combination giving a non-progressive order ofexposure aperture. In other words, each of the four frames of the cyclemay be photographed through a. different iris opening and consequentlyhave a different depth of focus, these depths of focus varying innon-progressive relationships.

By differently shaping and proportioning the cam faces, greater orlesser amounts of variation may be had between successive frames so thatany particular type of image may be selected and made to predominateweakly or strongly.

Since it is desirable that the projected images on the screen be ofsubstantially uniform density so as not to cause eye strain by reason ofsharp variations in the amounts of light projected on the screen, Iprefer to print the negative obtained by my foregoing process in such amanner that the resulting positive obtained therefrom has substantiallyuniform density throughout. This may be done through use of the methodsand apparatus disclosed in my United States Letters Patent No.2,173,866, issued September 26, 1939, and can easily be done by varyingthe printing lights so that the frames of the negative which tively flatcompared to those other are thin in density are printed with a lowerprinting light than are the thick density negative frames. By thusrecurrently regulating the printing lights, I produce a positive whichis substantially uniform in density, but in which the variations indefinition present on the negative are carried into the positive so thattheplastic effect obtained by my film is retained.

Since in a complete photoplay, there are many scenes and moods, it ispossible to produce by myinvention individual scenes with differentcharacteristics which will properly portray the required mood, and causea proper response in the viewer.

As illustrative of one of the many combina tions possible, I have shownin Fig. 6 two frames of a film photographed as follows: The upper framewhich I term frame I has been photographed with'both the foreground andbackground in sharp focus, and frame 2 has been photographed with thebackground in focus, but the foreground diffused.

While in most instances, I prefer to focus the camera on the backgroundas shown in the drawings, or on the middle background, I may for certainpurposes focus the camera on the foreground or other plane in the field,but unless a plural-focal lens or special optical image system isemployed, it is always preferably focused on a plane at areasonabledistance behind the foreground object plane.

While the photographic operations heretofore described are veryeffective and materially add to the naturalness of the picture as awhole, and especially add to the plastic relief of foreground figures onoff-focus depth planes, I'have found that when the lens focus is fixedand held on any one object throughout the successive exposures, thatobject will not have the same roundness as the other objects in thepicture. Although it may appear separated by the depth introduced intoother planes, it remains individually relaoblects which have variousimage formations among the several frames, this being particularly sowhen sharp focus is set on a close-up object. This condition ispartially corrected by focusing the lens in space between particularplanes, but not all scenes can be so focused on, and when living actorsor movement exists within the scene, it becomes desirable to have theobject of primary attention in predominating clarity of focus whilealso, of course, producing the plastic efiect.

I have found that this combination can be satisfactorily effected in anordinary camera provided with my adjustable iris by using a plural-focaloptical system in connection therewith, in which an area of the lenssystem is focused most sharply on a near plane and another area of thelens system is focused most sharply on a more distant plane.

While various kinds of plural-focal lens attachments may be used, Iprefer to use an optical combination such as illustrated in Figs. 4 and5 of the drawing. I provide a strip of thin optical glass l2 immediatelybehind the rearmost element of the lens and in front of the iris. Thestrip l2 may be attached to the iris mount in any convenient manner, andpreferably in vertical position as shown. The width of the strip i2 ismaterially less than the diameter .of the lens, although vertically itcovers the lens while leaving the sides R and L thereof uncovered.

of moving the film closer to the lens. The plate I2 acts tomove thefocal point of that part of the lens system C aligned therewith back anamount equal to approximately one-third of the thickness of the plateP2.

The image, formed by the rays passing through the center of the lens andthe strip I2, is focused on a plane behind the plane upon which'theimages formed by the rays passing through the portions, R and L of thelens are focused. The result of this combination is that the rayspassing through the center C of the lens form a sharp image ofbackground objects on the film, while the rays passing through the lenssides It and L form sharp images of the foreground objects. Thus, in asingle exposure through my pluralfocal lens with the iris wide open, Iproduce on a single frame a picture consisting of aplurality of imageseach of which has the objects of a different plane in sharpest focus.

As one example of the many combinations possible with a plural-focallens and an adjustable iris, I give the following illustration. Assuningthat a cam similar to 52 is used in connection with the iris and a geartrain is employed which provides one complete revolution of the cam toevery four frames of film exposed, it will be evident that the irisopening will vary in position between circles 6 and l as illustrated inFig. i. If frame 8 of the him is exposed with the iris expanded, asshown by circle 6, then frame it will be exposed with the iris in thecontracted position of circle l. Frames 2 and will be exposed atintermediate positions of the iris aperture. The result will be thatframe i will bear a compound plural-focal image made up of the threeimages photographed through the portions 0, L and R of the lens, frame 3will have a single sharp focus taken only through the portion C of cothe lens, while frames 2 and i will each have As is well known, theinsertion of a glass medium in an optical path serves to move thefocalpoint away from the lens which is theequivalent images photographedthrough the portions 0 of the lens, and lighter images produced throughthe portions R and L of the lens. Thus it will be seen that when theframes are projected, a composite, picture is produced on the screenwhich has an illusion of natural depth throughout.

While I have described my invention as adapted for use with a motionpicture camera suitable for ordinary action shots, it will beunderstood, of course, that my invention is equally applicable to stopmotion photography such as is commonly used in the production ofanimated cartoons, miniatures, still life, lettered titles, and thelike. When employing the method of my invention in this type ofphotography, no special type of apparatus is needed for adjustment orvariation of the iris, or for moving the camera as the case may be,since the adjustments may be made manually between exposures. Likewise,I preferably photograph all of the frames directly to a uniform density,irrespective of the variations in the iris aperture. I control thetiming to reciprocally vary the duration of exposure by varying theamount of shutter opening for the various exposures to compensate forthe variations in aperture size. It Will be understood, of course, thatthe same range of combinations is possible in stop motion photography asis possible in action photography of the type heretofore dealt with, andthat the film of my invention produced by this means is similar to thatproduced by the methods previously set forth.

While I have given numerous specific examples of my invention, it is tobe understood that they are byway of illustration only, and that myinvention is not to be restricted thereto, but is to be afforded thefull scope of the appended claims.

' the illusion of depth, which includes: varying the depth of focus ofthe camera during the production of said images so that the images ofone series are exposed with a depth of focus different from that usedfor another series of images, and adjusting the duration of exposure ofsaid film to maintain each of the images of each of said series insubstantially uniform average density.

2. The method of producing a cinematographic film having a plurality ofintermingled images of different types aligned thereon, which film uponprojection will produce a motion picture having the illusion of depth,which includes: varying the depth of focus of the camera during theproduction of said images by changing the size of the exposure apertureof the camera so that framed images of one type are exposed with a depthof focus different from that used for framed images of another type, andadjusting the duration of exposure in accordance with the change in sizeof the exposure aperture to produce on said film images of substantiallyuniform average density.

3. The method of producing a cinematographic film having a plurality ofintermingled images of different series aligned thereon, which film uponprojection will produce a motion picture having the illusion of depth,which includes: exposing said film through a camera lens partiallycovered by an optical element which modifies the length of the opticalpath of that portion of the lens which it covers, whereby differingcomponents of a local image are differently diffused, and varying thedepth of focus of the lens during the production of said images so thatthe images of one series are exposed with a depth of focus differentfrom that used for another series of images.

4. The method of producing a cinematographic film having a plurality ofintermingled images of different series aligned thereon, which film uponprojection will produce a motion picture having the illusion of depth,which includes: exposing said film through a camera lens which hasextended substantially vertically across a central portion thereof arefractor having plane parallel faces whereby different areas of thelens are differently focused, and varying the depth of focus of thecamera during the production of said images so that the images of oneseries are exposed with a depth of focus different from that used foranother series of images.

5. The method of producing a cinematographic film having a plurality ofintermingled images of different series aligned thereon, which film uponprojection will produce a motion picture having the illusion of blendeddepth, which includes: varying the depth of focus of the camera duringthe production of said images by nonprogressively varying the size ofthe exposure aperture of the camera so that the images of one series areexposed with a depth of focus different from that used for anotherseries of images, and adjusting the time of exposure in accordance withthe change in size of the exposure aperture to produce on said filmimages of substantially uniform average density.

6. The method of producing a cinematographic film having a plurality ofintermingled images of different series aligned thereon, which film uponprojection will produce a motion picture having the illusion of depth,which includes: varying the depth of focus of the camera during theproduction of said images so that the images of one series are exposedwith a depth of focus different from but including that used for anotherseries of images, and adjusting the duration of exposure of said film tomaintain each of the images of eachof said series in substantiallyuniform average density.

7. The method of producing a cinematographic film having a plurality ofintermingled images of different series aligned thereon, which film uponprojection will produce a motion picture having the illusion of depth,which includes: focusing a motion picture camera upon a foregroundobject of the scene to be photographed, varying the depth of focus ofthe camera during the production of said images so that the images ofone series are exposed with a depth of focus different from that usedfor another series of images, and adjusting the duration of exposure ofsaid film to maintain each of the images of each of said series insubstantially uniform average de.1sity.

8. The method of producing a cinematographic film having a plurality ofintermingled images of different series aligned thereon, which film uponprojection will produce a motion picture having the illusion of depth,which includes: focusing a motion picture camera upon a backgroundobject of the scene to be photographed, varying the depth of focus ofthe camera during the production of said images so that the images ofone series are exposed with a depth of focus different from that usedfor another series of images, and adjusting the duration of exposure ofsaid film to maintain each of the images of each of said series insubstantially uniform average density.

IVAN M. TERZWILLIGER.

